1. Field of the Invention
This invention relates to the field of gauges for adjusting the position of one attachment location with respect to a reference position. More particularly, the invention pertains to a throttle valve adjustment gauge for checking and setting the position of the attachment of a control rod on a carburetor throttle lever.
2. Description of the Prior Art
Conventionally automatic transmissions have a vacuum diaphram attached directly to the transmission case for controlling the position of the throttle valve, which determines the automatic shift scheduling and shift quality. In such transmissions, engine vacuum sensed at the carburetor is a reliable indication of engine output torque and provides a satisfactory means by which the position or state of the throttle valve may be controlled.
In certain transmissions particularly power transmissions that produce overdrive gear ratios, engine vacuum is not an accurate indication of engine torque and cannot be relied on to control the position of the transmission throttle valve. For this reason a mechanical throttle valve actuator in the form of a control rod extends from the throttle valve on the transmission to the throttle lever on the carburetor. By means of the control rod the position of the carburetor throttle is transmitted to the transmission throttle valve and is used as a signal for controlling automatic shift scheduling and shifting quality instead of engine vacuum. The mechanical linkage between the transmission and the carburetor requires initial adjustment when the vehicle is assembled and occasional readjustment whenever the carburetor idle speed setting is changed. Misadjustment of the linkage can produce objectionable shift quality. It is necessary, therefore, that an objective indication of the location of the attachment of the throttle valve control rod on the throttle valve lever with respect to a reference position be available when the vehicle is assembled and during certain service operations. The reference position of the throttle lever might be the engine curb idle position with the engine off.